Lindholm Heléne, Ejeskär Katarina, Szekeres Ferenc
Department of Biomedicine, Translational Medicine, School of Health Sciences, University of Skövde, 54145 Skövde, Sweden.
Med Int (Lond). 2022 Sep 2;2(5):27. doi: 10.3892/mi.2022.52. eCollection 2022 Sep-Oct.
The alpha subunits (ATP1A1-3) of Na/K-ATPase binds digitoxin with varying affinity. The expression levels of these subunits dictate the anticancer effects of digitoxin. In the present study, three pancreatic cancer cell lines, AsPC-1, Panc-1 and CFPAC-1, were used to investigate the effects of digitoxin in relation to the expression of the subunits ATP1A1 and ATP1A3. Cell viability and intracellular calcium concentrations was measured in relation to the gene and protein expression of ATP1A1 and ATP1A3. Digitoxin was used to treat the cells at concentrations of 1-100 nM, and the intracellular calcium concentrations increased in a concentration-dependent manner in the Panc-1 and in the CFPAC-1 cells with treatment at 100 nM. In the AsPC-1 cells only the supraphysiological concentration of digitoxin (100 nM) resulted in a decrease in the number of viable cells (unviable cells increased to 22%), whereas it had no effect on intracellular calcium levels. The number of viable Panc-1 and CFPAC-1 cells decreased after digitoxin treatment at 25-100 nM (unviable Panc-1 cells increased to 33-59%; unviable CFPAC-1 cells increased to 22-56%). Digitoxin treatment also affected the transcriptional expression of the and subunits. In Panc-1 cells, gene expression was negatively associated with the digitoxin concentration (25-100 nM). In the AsPC-1 and CFPAC-1 cells, the expression of the gene increased in the cells treated with the 100 nM digitoxin concentration. The protein expression of ATP1A1 and ATP1A3 was not altered with digitoxin treatment. The basal protein expression of ATP1A1 was high in the AsPC-1 and CFPAC-1 cells, compared to the Panc-1 cells, in contrast to the basal expression of ATP1A3, which was higher in the Panc-1 cells, compared to the other pancreatic cancer cells used. On the whole, the present study demonstrates that the high expression of ATP1A3 renders pancreatic cancer cells more susceptible to digitoxin-induced cell death. The findings suggest that the expression of ATP1A3 may be used as a marker for tumor sensitivity to digitoxin treatment, where a high expression of ATP1A3 is favorable for the anticancer effects of digitoxin.
钠钾ATP酶的α亚基（ATP1A1 - 3）以不同亲和力结合洋地黄毒苷。这些亚基的表达水平决定了洋地黄毒苷的抗癌效果。在本研究中，使用了三种胰腺癌细胞系AsPC - 1、Panc - 1和CFPAC - 1，来研究洋地黄毒苷与ATP1A1和ATP1A3亚基表达相关的作用。测量了细胞活力和细胞内钙浓度与ATP1A1和ATP1A3基因及蛋白表达的关系。用浓度为1 - 100 nM的洋地黄毒苷处理细胞，在Panc - 1和CFPAC - 1细胞中，100 nM处理时细胞内钙浓度呈浓度依赖性增加。在AsPC - 1细胞中，只有超生理浓度的洋地黄毒苷（100 nM）导致活细胞数量减少（死细胞增加到22%），而对细胞内钙水平无影响。在25 - 100 nM洋地黄毒苷处理后，Panc - 1和CFPAC - 1细胞的活细胞数量减少（Panc - 1死细胞增加到33 - 59%；CFPAC - 1死细胞增加到22 - 56%）。洋地黄毒苷处理还影响了α和β亚基的转录表达。在Panc - 1细胞中，α基因表达与洋地黄毒苷浓度（25 - 100 nM）呈负相关。在AsPC - 1和CFPAC - 1细胞中，100 nM洋地黄毒苷浓度处理的细胞中β基因表达增加。洋地黄毒苷处理未改变ATP1A1和ATP1A3的蛋白表达。与Panc - 1细胞相比，AsPC - 1和CFPAC - 1细胞中ATP1A1的基础蛋白表达较高，而与其他所用胰腺癌细胞相比，Panc - 1细胞中ATP1A3的基础表达较高。总体而言，本研究表明ATP1A3的高表达使胰腺癌细胞对洋地黄毒苷诱导的细胞死亡更敏感。研究结果表明，ATP1A3的表达可作为肿瘤对洋地黄毒苷治疗敏感性的标志物，其中ATP1A3的高表达有利于洋地黄毒苷的抗癌作用。
